I am trying to send back the value of a selected item in Drop Down List back to an Action method in my controller using jQuery Ajax in an MVC4 web application. I have a Drop Down List called MeditechDropDown and here is my jQuery function that is not quite working. I manage to reach my Action method but the value coming in is null.

jQuery(document).ready(function () {
    $("#MeditechDropDown").change(function () {
        $.ajax({
            url: "/Home/PopulateEmailAddressUI",
            data: JSON.stringify('id=' + $(this).val()), // Send value of the drop down change of option
            type: 'POST',
            contentType: 'application/json; charset=utf-8',
            success: function (data) {
                // Variable data contains the data you get from the action method
            }
        });
    });
});

The action name is PopulateEmailAddressUI. Will someone kindly shed some light on what I am doing wrong? I know I am not writing my jQuery function correctly. Many thanks.

I have written some successful jQuery ajax calls in .NET MVC4. This is what they look like:

$('#projectList').on('click', 'li', function () {
        pid = $(this).data('id');

        $.ajax({
            type: 'POST',
            url: '/Admin/GetProject',
            data: '{ id: ' + pid + ' }',
            contentType: 'application/json; charset=utf-8',
            dataType: 'json',
            success: function (data) {
                projectRetrieved(data);
            }
        });

    });

Controller:

        [HttpPost]
        public ActionResult GetProject(int id) {
            string connStr = ConfigurationManager.ConnectionStrings["Conn"].ConnectionString;
            SqlConnection conn = new SqlConnection(connStr);

            string sql = "SELECT * FROM [Portfolio] WHERE [id] = @id";
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            da.SelectCommand.Parameters.Add(new SqlParameter("@id", id));
            DataTable dt = new DataTable();

            conn.Open();
            da.Fill(dt);
            da.Dispose();
            conn.Close();

            return Json(objConv.DataTableToArrayList(dt), JsonRequestBehavior.AllowGet);
        }

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